The "Crouching Tiger” standoff heated up Tuesday after the four largest exhibitors in the U.S., AMC, Regal, Cinemark and Carmike, pledged not to show the martial arts sequel next year. That represents 257 of IMAX’s 418 U.S. screens, and these theater chains were joined by Canada’s largest exhibitor Cineplex, and Europe’s second largest theater chain, Cineworld, in a boycott that has grown international in scope.